SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '819bd6e5425294a91f08c0c447409366fb17f64e9775f7006a3c4c278879bcfd' 
  AND token = 'BLyHnuFViFQ3TBHPVTt0AeBWziWmCIQGK2aNaZ7pwg8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}